[LONDON] Global clean energy investment in the second quarter of this year continued to lag behind that of last year due to a sharp rise in the US dollar and share price volatility, research showed on Friday.

Investment in renewable energy such as wind and solar power and biomass fell to US$53 billion in April to June, 28 per cent lower than US$73.6 billion in the same quarter last year, Bloomberg New Energy Finance (BNEF) said in a quarterly report.

The rise in the US dollar has reduced the value in dollars of deals outside the United States and volatile stock markets, particularly in China, has held back equity raising by clean energy companies and funds. "The first two quarters of 2015, taken together, have seen investment down 18 per cent compared to the first half of last year," said Michael Liebreich, chairman of the advisory board at BNEF.

"It is possible that the Q1 and Q2 2015 figures will be revised up a bit in due course as some more deals are disclosed, but we have been predicting since January that this year would see lower investment than 2014 because of the strong dollar." Despite this, the second quarter saw record high investment in Chile. Clean energy investment there rose by 56 per cent compared to last quarter and 40 per cent year-on-year to US$1.3 billion.

Investment in China was at US$15.5 billion, 14 per cent higher than the previous quarter but 36 per cent lower than Q2 2014.

Other countries also saw investment drop from last year. Investment in the United States was down 21 per cent compared to Q2 last year at US$9.4 billion, while Japan's investment was down 10 per cent year-on-year at US$8.1 billion.

Small-scale solar projects worldwide, however, experienced a 29 per cent rise in investment from Q2 2014 at US$20.4 billion, as rooftop panels became much less costly after recent price falls.

BNEF said global investment should start growing again as the cost of solar and wind power continue to fall. It forecasts that two thirds of US$12.2 trillion investment in energy generation capacity between now and 2040 will be in renewables.

REUTERS